JONESBORO – The search for a missing teenager from Columbia shifted to an intensive, coordinated effort to cover more than 200 miles of Washington County’s rural roads by foot and all-terrain vehicles Wednesday, the fourth day since Krystal Higgins disappeared.

Local authorities with the Maine State Police and Maine Warden Service called in more assistance statewide, including the commanding officer of the Criminal Investigation Division, wardens out of Greenville and engineers from the U.S. Cellular phone company.

The law enforcement officers in turn called on more than 70 civilian searchers from area fire departments and ATV-club members who are experienced on Washington County’s vast network of dirt roads.

Authorities are still gathering information through interviews and have not focused on a single theory to determine where or how the 17-year-old disappeared Saturday around midnight.

Driving her own car, Higgins dropped off some friends at one house in Columbia, told them she was heading home but failed to reach her residence on Saco Road.

Tuesday’s search involved five game wardens, five state troopers and three detectives. Wednesday, the professional presence escalated to 10 wardens and about nine state police members.

“The information we are receiving is not leading us in any specific direction,” said state police Lt. Dennis Appleton, head of the state’s criminal investigation unit, Wednesday afternoon.

“The fact that we have people around here searching is based on one of many, many scenarios.

“We have the warden service available to us. If this individual has had a car crash, if her car is off the road, we have the ability to search for that,” he said.

The command post to coordinate the ground search switched Wednesday to the Jonesboro office of the Maine Department of Inland Fisheries and Wildlife. There, investigators worked from one room and wardens from another, all surrounded by topographical maps, computers and phones.

Today, the command post will return to its Tuesday location at the Pleasant River Ambulance Service building on Route 1 in Columbia. That will put the searchers in a location more central to the search area.

As the hours mount with no word from Higgins, as authorities remain puzzled by the whereabouts of her vehicle, many in Columbia and surrounding small towns hope that some leads will turn up.

“If Krystal were a wild child who might just drive off and do God knows what, this would be different,” said Tammy Beal, a cashier at the Irving gas station and store in Harrington, where Higgins is known as a frequent customer. “But she wasn’t like that at all.”

Higgins’ friends and colleagues have described her as a smart, dependable young woman who never showed up late to work. She is street-savvy, one of her employers said Wednesday, but perhaps too trusting at the same time.

Some of the friends she drove around with on Saturday evening, before she left them around midnight, have told police investigators that she was drinking that night.

Police would not confirm that.

The Irving station on U.S. Route 1 is a center point in the investigation, partly because Higgins was recorded there four times on video surveillance cameras during the evening.

It is known Down East as a place where young people can get Subway sandwiches, meet up and mingle. From Irving, they decide where to go next, circling back later to see if they missed anything or anyone.

The Irving station is about six miles from the house where Higgins has been living with a friend’s family since April. She is legally emancipated from her own parents.

Her imprisoned father has just a few months left on his sentence at the Down East Correctional Facility in Machiasport. Higgins apparently has been looking forward to reuniting with him, one friend said Wednesday.

She also was anticipating a Sept. 14 date to see the Red Sox play in Boston, said Angela Rackliff, a co-worker at the Pleasant River Drive-In, who secured the tickets recently.

“She printed out the stadium map to find our seats,” Rackliff said. “Even the day she disappeared, she was talking about the fun we are going to have in Boston.”

Higgins made a cellular phone call to Rackliff at 11:57 p.m. Saturday, leaving a message to ask if Rackliff wanted a ride home. That was Higgins’ last known communication.

She made six or seven more calls to two friends after 1 a.m. but did not leave any messages. The last call was made at 1:48 a.m., according to Warden Lt. Patrick Dorian.

The U.S. Cellular company sent three technicians to the command post Wednesday. They have been working with wardens to identify the “100 or so dead spots” within the search area where cell phones do not get signals.

Authorities believe that Higgins’ calls after 1 a.m. came from a cone-shaped geographic area that is most likely within 12 to 24 miles northeast of the Milbridge tower, Warden Joe McBrine said.

A more precise location is indeterminable, McBrine said, depending on whether she was calling from a height of land or in a low spot.

Higgins was driving a gold, two-door, 1997 Chevrolet Cavalier with Maine license plate No. 5794-LQ.

The car’s description and information has been lodged in a national crime computer, Appleton said. If the car is stopped or checked, a match will surface.